Day of Disgrace
Historical term referring to April 28, 1952, when the San Francisco Peace Treaty restored sovereignty to mainland Japan but left Okinawa under U.S. administration, seen as a day of humiliation in Okinawa.
In Okinawa, April 28th is sometimes called the 'Day of Disgrace'.
Compound of 屈辱 (くつじょく, 'humiliation') + の (possessive particle) + 日 (ひ, 'day'). The term originated in Okinawa to mark the perceived betrayal of the 1952 treaty.